In short, Embark is a FREE mapping tool, which you can use to create waypoints, plan routes and use as a tracking tool when you're out on the water.

I've been playing around with it by creating routes from the OBC and Half Moon Bay to a few popular fishing spots, to give me an idea of how long it will take to get there, so I can plan my day accordingly.

A few screenshots of my different routes are below. 

When you zoom in, the maps are reasonably detailed and have all the appropriate safety markings on them. See a screenshot below of the Noises in the Hauraki Gulf, and the channel between Great Barrier and Little Barrier.

TL;DR:

If you were ever out on the water and needed a back up map, this would be my go to.

While competitor, Navionics, has a good following of app users, at $24.99 to download I think a lot of people will be giving the Embark app a try first!

 You pay for what you get.

 Includes almost daily data updates of bathymetric detail.. and sync of settings routes tracks map settings etc, between smart phones , gps units , tablets etc... then throw in live weather, tide and currents.. anchorages and a lot of other stuff.

 Then able to put in boat details/ specs.. draft, cruise speeds, fuel usage.. custom colour depths.. and that still doesnt cover everything.

 For $24...$10 per yr there after.. near cost of one burley bomb

 open cpn is as good as cmap.. latest LINZ maps.

 And there are several other similar programs available for both computer and smart phone/ tabs.

 Sry , but I have spent a lot of time on maps, both marine and land based, including DoC, topos etc

 With the combination of garmin and navionics .. both at top of the game, and considering the low cost as an app..

 Check out NWIA maps now available to buy.. and still not up to date..